Is elevated creatinine a reliable marker for methanol toxicity in nitromethane-containing model fuel ingestions in children?

CONTEXT

In the absence of a rapid serum methanol level estimation, it is difficult to assess the risk from unintentional childhood ingestion of model fuels containing methanol and nitromethane (MFNM). Previous reports have documented false elevations of serum creatinine from the nitromethane in these fuels, suggesting its utility as a readily available marker of significant methanol ingestion.

METHOD

We performed a 2-year retrospective chart review of cases of ingestion of MFNM in children, with both a methanol level and measured creatinine level.

RESULTS

Seven children, ages 19 months to 3 years, ingested MFNM. All seven children were seen in a hospital and had measured methanol and creatinine levels. All blood samples for methanol and creatinine were drawn within 3 hours of ingestion with methanol estimation delayed up to 24 hours. Creatinine ranged from 0.39 (0.034 mmol/l) to 10.7 mg/dl (0.95 mmol/l). All methanol levels were <10 mg/dl (0.31 mmol/l) or reported as negative. Fomepizole was initiated empirically in two patients due to delay in obtaining methanol analysis results.

DISCUSSION

Transient elevations of creatinine occurred in five of the seven children. Blood urea nitrogen was within normal limits, and there was no history of renal impairment in these children, suggesting the elevated creatinine was mostly related to nitromethane ingestion. No child had a significantly elevated methanol level.

CONCLUSION

Elevated creatinine level, as measured by Jaffe colorimetric method, is not a reliable marker for elevated methanol levels after unintentional ingestion of MFNM.